Shear and Dodge : Patellina, Leptothyrium, Peziza 149 



gular segments thus formed (test- fig. j) turn up or fold over 

 exposing the spores which are quickly dispersed when wet, as 

 they are surrounded by a mucilaginous substance which swells 

 very quickly on addition of water and causes the spores to be 

 pushed out and spread just as they are from the sporodochia. 



A 



Fig. 3. Pycnidia of Sclerotiopsis concava. a. Three pycnidia showing 

 characteristic dehiscence. b. Pycnidiuni after having discharged all of its 

 spores and dried, c. A pycnidiuni just previous to spore discharge, d. Pycnid- 

 ium after spore discharge and the breaking away of the segments of the wall. 



III. Ascogenous Stage, Pezizella lythri (Desm.) n. comb. 



The ascogenous stage has been found from the latter part of 

 July to October. So far as known at present the discocarps were 

 first described by Cooke & Ellis (1878). Ellis collected the speci- 

 mens on Oenothera in August. They occur frequently associated 

 with the other stages on dead leaves, petioles, fruit stalks and 

 small branches of Rubus, and are especially abundant on the 

 "bark" at the base of stems of living Oenothera and on the mid- 

 rib and petioles of Steironema. They are most easily seen in the 

 morning when the dew is on or after a rain when all the plant 

 parts are wet. The disc then appears white, about Yi-i mm. in 

 diameter and flat. The sides and short stalk-like basal portion 

 are light-brown or amber colored. When dry they may retain the 

 flat disc-shape, or the margin may become somewhat involute. 

 In the latter condition they closely resemble the amber colored, 

 hard resin-like dried sporodochia which are frequently found 

 side by side with the discocarps. The pycnidia are not uncom- 

 monly found on the same specimens with the other two forms. 

 Ellis evidently sometimes mistook the large dried sporodochia 

 for the Pezizella stage on stems of Oenothera which he dis- 

 tributed as No. 846, N. A. F. On the specimens of this number 

 in the herbarium of the U. S. Department of Agriculture there 



